Thatching Ant


Actual Size: 4 to 8 mm

Characteristics: Large heads with powerful jaws; usually both red and black in color.

Legs: 6

Antennae: Yes

Wings: Reproductives have wings.

Habitat: Builds large mounds using small twigs, pine needles, and other natural materials. Mounds can grow up to 4 feet wide by 2 feet tall.


  • Known for building some of the biggest ant mounds.
  • Can be aggressive and may bite when defending their nest.
  • Also commonly referred to as “mound ants”.

Thatching Ants in the Pacific Northwest

Also commonly referred to as “mound ants”, thatching ants are known for constructing large mounds using pine or fir needles, leaves, small sticks, and other organic debris. These ants may also nest in decayed logs or similar natural structures. Their colonies can persist for years and may contain tens of thousands of individual ants. Thatching ants typically feed on various insects, such as caterpillars, dead moths, and small beetles. Some people have also witnessed these ants carrying live prey into their mounds.

Thatching Ant Habitat

Thatching ants typically build their nests in forests, yards, and other outdoor areas. Their mounds can measure up to four feet wide by two feet tall, and they are typically made from small sticks and pine needles. Thatching ants may also live in decomposing trees or soil, and they typically feed on other insects. Though these ants can be beneficial by helping control insect populations, their nests can be a major eyesore for homeowners dealing with an infestation.

Thatching Ant Behavior, Threats, or Dangers

Thatching ants can be aggressive toward humans and pets. If provoked, they may deliver a painful bite and spray the bitten area with formic acid, which can result in sore blisters. Additionally, thatching ants can cause damage to yards by destroying plants, seedlings, and the buds of fruit trees. Though these ants can be beneficial to the ecosystem by eliminating harmful insects, they can be extremely bothersome if they take up residence near your home. If you spot thatching ants on or around your property, a professional ant exterminator can help you remove these pests.